1. Technical Field
The present disclosure relates to lasers.
2. Description of Related Art
Because of the high power levels available, a variety of lasers are frequently used in industrial applications such as cutting and welding, and in military applications such as laser weapons.
Most of the high power lasers are multi-mode lasers, and the laser beams have large divergence angle, shallow depth of focus, low stability, and high power density loss during long distance transmission.
What is needed, therefore, is to provide a laser of which the laser beam has small divergence angle, small spot size, long depth of focus, and low power density loss during long distance transmission.